Selective signaling system.



PATBNTED JULY 14, 190s.

' G. ,BABGOGL SBLEGTIVB SIGNALING SYSTEM.'

1 AYRLIQATION FILED JULY 17, 190s.

I-IivanTnr GarrisnnlE abnnBK WiTnE'ssas' l' Y y urnqg I UNITED sTATEs PATENT OEEICE. i

GARRISON BABCocnjOFfoHIo-AGO, ILLINOIS, AssIGNOE To sTRoMBERG-CARLSON TELE- PHONE MANUFACTURING COMPANY, OEROCIIESTER,` NEW YORK, A CORPORATION oF l NEW YORK.

' Specicationof Letters Patent.

sELEcTIvE SIGNALING SYSTEM.

Patented July 1-4, 1908.

Application led July 17, 1903. Serial No.- 166,028.

To alt whom it may concern:

Be it known that I, GAimisoN BABCOCK,

citizen of 'the United States," residing at Chi-` cago, in the countyof Cook and State of Illinois, have invented a certain new and useful Improvement in Selective Signaling Systems, of -.which the following is a full, clear, con oise, and exact A description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to selective signaling i, systems, andhas for its objectimproved central exchange apparatus and connections, whereby the central operatory g may more readily establish circuit vconditions necessary for such systems. i

My invention is articularly ada table to a system as described in my Patent o. 763,351 issued June 28, 1904, in whichit is setting-up current, locking current,

signaling current and restoring current into the line,

y conversation and to restore the lsystem to its normal condition after conclusion of the conversation. y

The features of my invention are embodiedin .an improved operators c ord circuit. In the cord circuit employed in the system described in the patent above referred to, the necessary currents could be sent from only one of the cord lugs, and when a subscriber was answered with this plug and desired con' nectioii with aparty line subscriber, it was necessary fior the central operator tol withdraw the answering lug and insert it in the s ringjack connecte with the` line leadingto tiie desired subscribers substation. If this was not done, it Wasnecessary for herto em-` ploy the calling plug connected -to another cord circuit Also, when subscribers of different party lilies were connected to ether for conversation, itwas necessary for t e operator, in order to restore both party lines to their normalcondition, to restore first the line connected with the calling plug and then to withdraw this plug for connection with the other party line to restore -this line. 4 This interchange of plugs and cord-.circuits caused great waste of time besides being very-apt to v necessary' for the centralo'perator to successively send `'gether, to send the necessary currents into the lines from either plu or simultaneously through' both plugs of te cord circuit emplciyed, thus saving a great deal of time. 1 y

t is 'sometimes desirable to associate a party line system of one manufacture with a metallic telephone system of another manufacture. Heretofore, where systems of different manufacture have been operated together, circuit and apparatus changes were 4necessary in the systems to accommodate the circuits of one system to those of another and to ada t the apparatus of one system to receive an fit the ap aratus of the other. I employ means where y such changes may be 'avoided and I provide a plug which fits the spring-jacks connected with the telephone system with which it is desiredto associate t e partyiline system. This plu may be lconnected in bridge of the callin p u of m improved cord circuit. Thus, W en `t e cal ing subscriber of a party line desires connection with another party line subscriber, the

calling plug ada tedfor the party line system is employed. S Ould the calling subscriber, however, call for connection with ya subscriber connected with a single subscriber `metallic line, for instance, the substitute adapted for' that line is employed.

Asaine plug is employed as an answering plug `when the call is initiatedfrom a metallic single subscriber line. It `.is to be borne in mind, however, that in many cases the jacks used for both single substationv lines and polystation lines are of the same manufacture and adapted to coo erate with interchangeable plugs, in whic Leases the auxiliary plug 123 is unnecessaryand only the plugs 8 and 9 are connected .to the cord circuit.

I shall describe my invention more clearly and fully by reference to the accompanying drawing, in which I have shown two party linesubscribers B and C connected together through the cord circuit, these subscribers being connected with the central exchange through limbs 29 and 30 of the metallic tele- `hone lines 1407 and 207, respectively. I 'liave also shown ametallic line 306 leading from the central exchange to the substation A. This line 306 terminates in a springjack 28, which can only be engaged by a lug of like manufacture. The limbs 29 an 30 of the party line terminate in jack springsv 31 and 32, respectively, and a third jack spring 33 is normally in connection with the jack spring 31 to connect the line indicator 34 with the limbs of the line.

The apparatus at substation A includes va receiver 1, normally suspended from a switch hook 2, an induction coil 3, transmitter 4, battery 5, generator 6, and signal bells 7. The cord circuit includes an answering plug 8, a calling lug 9, a battery 10, a make and break switc 11, a restoring key 12, circuit changing keys 13 and 14, a ground ringing key 15, a metallic ringing key 16, an o erators listening key 17, an operators talking set 18, a ringing generator 19, and a clearingout drop 20.

At the party line substations Band C I have diagrammatically illustrated the apparatus employed. The windings of an electromagnet 35 are permanently connected in bridge of the linbs 29 and 30. This electromagnet is provided with a polarized armature 36 pivotally mounted at 37 and provided with a lever 38. A ratchet wheel 39 is mounted upon a shaft 40 which carries at its .-upper end a switch arm. 41. A, suitable spring 42 tends to cause a clock-Wise rotation of the shaft 40 and the parts mounted thereon, the clock-wise rotation of the switch arm 41 bein limited, however, .by the insulated norma contact 43. The lever 38 is provided at its extremity with a pivoted dog 44, a stop 45 being provided to limit the backward swing of this dog. A relatively stationar pawl 46 is mounted upon the frame of t eselective instrument, this pawl being provided with a rojecting pin 47 adapted to be engaged by a epending arm 48 forming a part ofthe dog 44. The passage of a currentrthrou h the coils of the electromagnet 35 in one ireetion causes a movement of the lower extremity of the lever toward the shaft 40, whereby the dog 44 is made toengage a tooth of the ratchet wheel to cause a one step forward advancement thereof, the VpaWl 46 dro pin into the next successive tooth to check) anrgl prevent the backward rotation of the ratchet wheel upon the denergization of the electromaglnet 35, suitable spring mechanism, not

shown, being provided to cause the armature 36 Iand the lever 38 to return to theirnormal intermediate position.

An energizationof the electromagnet 35,

`dupe to the passage of a current therethrough in a reverse direction causes a movement of the extremity of the lever 38 away from the shaft 40 whereby the. depending arm 48 of the dog 44 engagesl the pin 47 carried by the pawl 46, whereby the ratchet wheel 39 is disengaged'from both the dog 44 and the pawl 46 to permit the clock-wise rotation of the Shaft 40 and the parts carried thereby, due to the tension of the spring 42. A trip lever 49 is pivotally mounted at 50 and a trip arm 51 is carried by the shaft 40 in suchla position as to engage the end of the trip lever 49 when the switch arm 41 is inits normal position, as shown. A second electromagnet 52 serves, when energized by the passage of an electric current therethrough, to cause an attraction` of its armature 53 to which is attached the switch arm 54, this switch arm being normally held in its retracted position by means of a spring 55. The front contact 56 for the switch arm 54 is connected with the normal contact 43. When the trip lever 49 is not engaged by the trip arm 51 the trip lever 49y serves to enga e the end of the switch arm 54 to retain the atter in its forward attracted position after having been brought into this position, due to theenergizationv of the electromagnet`52.

Concentrically mounted with respect to the shaft 40 is a metal ring 57, this ring being provided with a series of equally spaced holes 58, the pitch of which is equal to that of the teeth ofthe ratchet wheel 39. A contact pin 59 is inserted in one of the holes 58. At each of the substations connected with any one line a similar pin is inserted in one of the holes of the ring 57, the pin at each substation, however, being inserted in a different hole from that in which a pin at any other substation is inserted, thus: The first substation connected with a given line may have this contact pin 59 inserted in the first hole, the second substation may have this pin inserted in the second-hole, the third substation may have this in inserted in the third hole, and so on. he pin at substation C only is inserted in the seventh hole of the ring 57. The contact 43 is insulated from the metal ring 57, and the ring 57 as well as the contact 43' is insulated from the frame of the instrument with which the switch arm 4 is in electrical connection.

A switch hook 60 serves when in its normal depressed position, due to the weight of the telephone receiver 61, to open a local circuit through the battery 62, the transmitter 63, and the primary 64 of an induction coil whose secondary 65 is adapted for inclusion in circuit with the receiver61. A condenser 66 is serially connected with the receiver 61. The call bell 67 is connected with the ground when the switch hook is in'its normal depressed position with the switch arm. A pulsating direct current generator 68 provided with an automatic switch 69 for opening the armature circuit when the generator 'is' not being operated is connected'with the subscriber C having not yet been signaledby the central operator. The operation and the various circuits may now be readily traced as follows: After having inserted the callingr plug 9 into the spring jack 70 connected with the line 207 leading to substation C, the operator sends a series of impulses over the line by actuation of circuit closing key 11.` This circuit may be traced as follows; from, the

positive side of battery 10, to 'conductor 71,.

to inner spring `72of the restoring key 12, to middle 'spring 7 3, conductor 74, inner spring 75 of lthe ground ringing' key 115, middlespring 76, conductor 77, outer yspring 78 ofl circuitchanging key 14 which isf depressed,

middle spring 79, c onductor '80, inner spring 81 of metallicringlng key 16, middle spring 82,'conductor 83, sleeve v 84, of plug9, jackspring 32 limb 30, conductor 85, -throughthe windings of electromagnet 35, to conductor 86, limb 29,-jackspring'31,;plug tip 87, conductor 88, middle 4spring 89, inner spring 90, conductor9 1, inner spring 92 'of key 14, outerI spring 93, conductor94, middle spring 95 of key 15,.inner spring 9 6, conductor 97 ,mid-

dle spring 98 of key 12, inner spring 99, conf ductor.100, and through key 11 back to the negative side of the battery 10. The passage of current through the electromagnet 35 in the direction caused by the closure of this circuit causes' an attractionl of the armature 36 to produce a one step lforward advance;-

ment of the ratchet Wheel 39 andthe switchl 15, may actuatethe signal bell 67. This signaling circuit 'may 'be traced as follows V From thefgenerator 1,9,.'to

. change to the generator 19.y Immediatelyconductor 101, to outerspring 102 ofkey15, to middle spring 76, conductor 77, outer vspring 78 of-key'14,' middlespring 79, 'conductor 80, inner spring 81, middle spring 82,

conductor 83, plug sleeve 84, 'jackspring 32,

' limb 30, conductor 85, conductor 104,.to `the shaft 40, switcharin 41, pin 59, through elec# tromagnet 52 to ground, and back through the ground conductor at thecentral" exupon the passage of current throughthis cir` cuit, electromagnet 52 will become energized to attract its armature 53, and switcharm 54 is engaged `arid retained by/the tripvl'ever 49, and they currentfrom conductor 85 divides,

part thereof passing,,as abovedescribed,

through electromagnet 5 2'1to ground, the other part passing through conductor. 105, triplever .49,switch -arm 54, spring 55, to switch spring 106, 'switch spring 107, through signal bell 67, 4to ground, the subscriber' being thus signaled. The call bells fat, no other substation connected with line` 207l willbe actuated for the reasonl'that none ofthe other switch arms 54 havebeen attracted bytheenergization of the associated electromagnet 52, substation C being the nal, can wit pin 59; f'Circuit` by depression verse with contactpiece 43.

The switch arms 41 at all the substations only one on the' line having a pin 59 adapted for contact with switch arm 41 at the'seventh impulse. The. subscriber C, upon 'receiving the signal and'removing his receiver from the hook, establishes thefollowing talking circuit through the cord apparatus withsubscriber B: from receiver 61 at substation C, through condenser 66, contact 56, switch arm 54, trip lever 50, through conductor 105,

-. conductor 85, limb 30, jack spring 32,'plug sleeve`f84, conductor 83, .middle s pring 82, inner spring 81, conductor 80, mid

ring 108 of key 13, middle spring uctor 110, through the sleeve of plug 8, through substation B following the same cir-' le spring 79, Ilnner sprlng 103, conductor 124, inner 109, concuits traced through substation C back to the .tip of the plug 8, through conductor 1 11,

middle spring 112, inner spring 113, conductor 114, inner spring. 115,-'rniddle spring92, conductor 91, inner spring 90 of key 16, middle spring89, conductor 8 8, plug tip 87 jack spring31, limb`29, conductor 86, conductor ondary winding 65, and back to the receiver at substation C. f

' 116, switch spring 117, switch spring 118, seci Upon the subscribers` concludingtheircon- 'l versation they actuate their substation generator 68, whereby the current is sent overl theline to actuate. the clearing-out drop 20. 'Before the operator, upon receiving this sigit is necessary that slierestore the system to its'normal condition. A subscriber will be unable to s` nal the operator when the plugs are out of t ejacks'unless 'switch arm' 41 is in contact with the contact 43,' central, therefore,`-actuates.restoring key 12 whereby a current; from battery 10 sent through the windin's Vof the electromagnet 35 .in a redgirectionto cause actuation of -either arm `in a direction away from, the ratchet wheel'f39`to allow spring- 42 to return the switch arm to its normal i on a party Aline move simultaneously with .impulses sent over the. line by closure of key ,11 at the central exchange, and u on restoringcurrentibeing sentr over the ine all the switch arms are returnedA to their normal position in contact draw .the plugs from the lines position. By actuation of restoring key-12 Y and either one or both ofthe circuit changing keys 13 and 14, `the central operator may send restoring current through either line 407 or line 207 or simultaneouslythrough both, being thus able to restore both lines without'reversing the plugs. ofthecord circuit or Without utilizing the calling plug from another., cord circuit. The restoring circuit through substation C, for instance, may be traced as follows: From the negative side of battery 10, to conductor- 119,` outer spring of restoring key. 12, middle spring 73,

vconductor 74, inner spring 75 of key 15,

middle s ring 76, conductor 77, outer s ring y 78, -midr le spzring 79,-conductor 80, inner spring 81 ofl ey 16, middle spring 82, conductor 83, plug sleeve 84, jack spring 32,-

limb30, through electromagnet 35, to conductor 86, limb 29, jack spring 31, lug tip 87, conductor 88, middle spring 89 o key 16,

inner Aspring 90, conductor 91 middle spring 92 of key 14, outer spring 93, conductor 94,

middle spring 95 of key 15, inner s ring 96,

conductor 97, middle lspring- 98 o key 12, outer s ring '121, to conductor 122, and to conduc or 7'1 back to the positive side of battery 10.l 'I o restore the apparatus at substation'B the opperatoryactuates both the re'- storing key 12 and the circuit changing key 13, the restoring current passing through substation B' throu h the same circuits as in substation C. e plugs may now be withdrawn and the lines are again in normal condition to give or receive calls.

When a party line system is installed to be operated in connection with a telephone system of dierent manufacture, I employ a substitute lug 123, which may be connected v in bridge o the calling plug 9 connected with If the line 306 leading to subscriber A be a metallic line the operator will signal subscriber A by actuation of metallic ringing ke 16 tofconnectv the generator ,19 across the si es of line 306 in a manner well known to l 40ans@ Skilled in the are Again, should Subscriber A, for instance, signalthe central operator, she would insert plug 123 in springjack 28 and if subscriber A desired connection withsubscriber B she would insert plug 8 into the jack connected with the line 407, whereupon the connections at substation B could be adjusted as hereinbefore described.

The system of my invention may thus be associated with any telephone system ofl different manufacture without changing any of the circuits or apparatus of either system, the ,merevuse of an additional plug ofva pattern corresponding to lthe different system'being necessary. f

I do not wish to be limited to the exact ar` rangement of apparatus and circuits as herein described, as chan es may readily be 'made without changing t e scope of the invention.

I claim as new, however, and desire to se`- cure by Letters Patent: y

1. In a tele hone system, the combination with la centra exchange, of telephone lines extending therefrom, a plurality of substations connected with one or more of said telephone lines, cord plugs at the central exchange, a cord circuit connecting` said (plugs, a source of current associated with sai cord circuit, circuit changing keys in said cord circuit whereby said source of current may be connected with either one of said plugs, a reversing key in said circuit, whereby the direction of current flow from said source may be reversed, a generator at the central exchange, one side of said .generator being tion with said circuit changing keys whereby the ungrounded side of said generator may be connected to one side of either of' said plugs, and an additional ringing ke whereb said generator may be connecte to bot sides of only one of saidA plugs, substantially as described.

2. In a tele hone system, the combination with a centra exchange, of telephone lines extending therefrom, a plurality of substations connected with onev or more of said telephone lines, cord plugs at the central exchange for connection with said telephone lines, a cord circuit connecting said plugs, a source of current' associatedwith said cord circuit, circuit changing keys in said cord circuit whereby said source of current may be connected with either'one of said plugs, a reversing key in said -circuit whereby the direction of current flow from said source may be reversed, a generator associated with saidcord circuit, one side of said generator being grounded, a ringing key acting in conjunction with said circuitv changing key, whereby the ungrounded side of said generator may be connected with one side of either of said plugs, an additional ringing key in said cord circuit, whereb said generator may be connected to two sides of one of said plugs, an o erators talking set, and an o erators ke or connecting said operator s set with sald cord circuit, substantially as described.

3. lIn a telephone exchange system, the combination with a central exchange, of telephone lines extending therefrom,l a plurality of substations connected with each of said telephone lines, a selective device at each substation and a polarized electromagnet for controlling said selective device, a relay and a signal bell at'each substation, cord plugs at the central exchange, a cordy circuit connecting said plugs, a source of current associated with said cord circuit, circuit changing keysl in the cord circuit whereby said source ofcurrent ma be connected simultaneously with both p ugs to send signaling current through the polarized electromagnets at the substations to cause actuation of substation apparatus, a reversing key in said circuit for reversing the current flow from said source to send current through the polarized electromagnets at the substation n ni a reverse direction to cause restoration of grounded, a ringing key acting in conjuncf central exchange havinga grounded terminal and a ringing key acting in conjunction with said' circuit changing .keys whereby the grounded side of said generator maybe connected to one side of both plugs whereby current will be sent to the relays at the substation to connectthe signal bells thereat in circuit, said generator current causing also actuation of the signal bell when connected in circuit.

4'. In a telephone exchange system, the combination with 'a central exchange, of telephone 4lines extending therefrom, a lurality of substations connected with eac of' said telephone lines, a selective device at each substation, a polarized electromagnet for controlling'said selective device, a relay 'and a signal bell at each substation, a cord circuit terminating in plugs, la source of current associated with said cord c1rcu1t,.c1rcu1t changing'keys in said cord circuit whereby said source 'may be connected with either one or both of said plugs, impulse mechanism for sending impulses from saidsource through the plugs and circuit changing keys into the line to cause actuations 'ofthe polarized electromagnets at the substations to set up the selective devices, a generator, and a ringing keyior connecting said generator through the circuit changing keys with either or both of. said plugs, actuation of said ringing key causing current flow through the relays at the substation whereby said signal bells at the c nnected substations are connected in circ it and actuated by current from said generator.

5. In a telephone'exchange system, the combination with a central exchange, of telephone lines extending therefrom, a plurality of substations connected with each of said' telephone lines, a selective .device at eachv substation, a polarized electromagnet for controlling said selective device, a relay and a signal bell at eachsubstation, a cordcircuit f terminating in plugs, a' source of current assoclated w1th sald cord circuit, circult changing keys in said` cord circuit whereby said source may be connected with either. one or both of said plugs, impulse f mechanismv for sending impulses from said sourcel 4through the plugs and circuit changing keys into .the

line to cause 'actuationsl of the polarized electromagnets at the substations to set up thev selective devices, a generator, a ringing key for connecting said generator `through the circuit changing keys with either or both of said plugs, actuation of said ringing ke causin current to flow through the rela s at the sustations whereby said signal be ls at the connected substations are connected in circuit and actuated by current from said generator, and areverslng key for said cord circuit for reversing the current 'flow from party line substation, a polarized electromagnet for controlling said selective device, a re- 75 .lay and a signal bell at each` party line sub-l stationfa cord circuit terminating in plugs, a' source of current assoclated W1th said cord circuit, circuit changing keys in said cord circuit whereby said source ma be connected with either one or both of sai plugs, impulse mechanism 4for sending impulses from said source through the plugs and circuit changingkeys into the line to cause actuation of the polarized electromagnets at the substations to set up the selective devices, a generator, a ringing key for connecting said generator through the circuit changing keys with either or both of said plugs, actuation of said ringing key causing current flow through the. relays at the substation whereby said signal bells at the 'connected substations are connected in circuitl and actuated by current from said generator, a reversing key for said cord circuit lfor reversing the current flow from said source whereby saidr electromagnets at the substations are actuated in an opposite direction to restore the substation apparatus to its normal position, and an additional ringing key for connecting said generator with only one of said plugs.

7. In a telephone exchange system, the combination with a central exchange, of telephone lines extending therefrom and terminating .in substations, a selectivedevice at l --eachsubstation connected in bridge of the line limbs, a polarized electromagnet for controlling each selective device, a relay at each substation adapted-at a certain position of 'the selective device to be connected between 1'1'0 ground and one of said line limbsa signal bell controlled by said relay, a cord circuit at the central exchange, va source of current, two cord 'plugs yconnected by said cord circuit,

impulse. mechanism for causing impulses from said source to pass to the cord-circuit, circuit changing keys in said cordcircuit for allowing lpassage of said impulses to either or both of said plu s, said impulses causing actuation of the se ective devlces at the substations to connect the relays thereat in circuit, a generator for the cord circuit having one terminal grounded, a key forconnecting the other terminal of said generator with one side of the circuit chan ing keys whereby actuation of said keys wi lfcause current from said generator to flow into the line limb connected with the'relays at the connected substations whereupon said relays will become entive devices there'at t'o restore the substation ergized to eonnect the controlled signal bells ap aratus to the normal condition. 10 in circuit, current from said generator then n Witness whereof, l hereunto subscribe y causing actuation of said signal bells, andra my name this 13th day of July A. D., 1903. f' reversing key for reversing the current flow GARRISON BABCOCK.

to saidA oircuitchanging keys, Whereb re- Witnesses: verse impulses may `be sent to the su sta- LYNN A. WILLIAMS,

tionsto cause reverse movement ofthe selec- HARVEY L. HANSON. 

